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Castech Cylinder Heads

03GMC5.3

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03GMC5.3 Enthusiast

03GMC5.3

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03GMCSierraHeads017.jpg03GMCSierraHeads018.jpg03GMCSierraHeads019.jpg03GMCSierraHeads021.jpg03GMCSierraHeads022.jpg03GMCSierraHeads024.jpg03GMCSierraHeads026.jpg03GMCSierraHeads028.jpg03GMCSierraHeads030.jpg03GMCSierraHeads034.jpg03GMCSierraHeads035.jpg03GMCSierraHeads037.jpg03GMCSierraHeads038.jpg03GMCSierraHeads039.jpg03GMCSierraHeads040.jpgheaders.pngheaders2.pnghey guys, just figured i would post my personal experience with bad casting on my sierra heads to inform and hopefully help someone out that might run into the same issue. my truck is an 03 gmc sierra 5.3. bought it with 45k in 2007. i started to notice coolant was dissapearing and couldnt figure it out so i just kept topping it off. this went on for about 6 months untill one day i changed my oil and noticed it was a little chunky and realized something was wrong. i started doing research and found out that gm had some heads casted by CASTECH and they were cracking where the head bolts to the block. i took off my valve covers and sure enough...behind all the gunk and sludge...was the CASTECH stamp and there was a puddle of coolant sitting where the head studs were. i buttoned it back up and called the gm dealer where i purchased the truck. they told me that they needed to verify it which cost me $100, even though i knew what the problem was. they got back to me like 2 weeks later and said they would pay 10% of the $2800 bill. i told them that was obsurd considering a cylinder head is not a wear part and should not go bad. i got on the phone with gm directly and they said they know about the issue but they couldnt do anything about it. needless to say i was very frustrated. i had to way my options. i am 24 years old with a new to me truck low miles and a hefty payment. i dont have much money but am a pretty good mechanic and i love my truck. so i guess its obvious. i purchased refurbrished heads off ebay from a machine shop in texas who fixes the heads and re sells them. it cost me 440 shipped for new heads fully loaded. all i had to do was package mine up and ship them back. gaskets were another 300 and i decided to throw some headers on it. when i got my new heads they were mint...so i tore them appart and ported them...18 hours later i put them on with headers...another 16 hours...yes this is a long time but keep in mind i scrubbed and thoughroughly cleened EVERYTHING. took a while but was well worth it. i ran some castrol gtx through it for 1000 miles and flushed that out and now all i run is royal purple with a mobile 1 filter...i am a firm believer in that stuff....truck runs great and really rips now that its all clean in there and im sure the porting and headers help too...i hope this might help some people. if you have some mechanical aptitude its not that bad of a job just time consuming and the head bolts are a b to torque especially the last 45 degree turn. just take your time and make sure its done right.i will try to post some pics.

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fatalwishes Enthusiast

fatalwishes

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Those heads come with the rockers and rods as well?

 

How did you adjust the rockers? 1/2 turn or 3/4 turn after touching the rods?

 

 

What brand headers and how much were they?

cghbuilder86 Enthusiast

cghbuilder86

Posted
Posted

Dang, I hope my truck doesn't have this issue. '04 5.3 80k miles. About 6 months ago I started loosing some coolant, asked the dealership about it and they recommended a GM seal tab in the coolant system. Hasn't lost any since. I still worry about those heads though. I wonder what the best option would be for somebody uncomfortable working on the motor themselves? You have to wonder if a motor went 100,000 miles before having serious problems, how much money would you want to put into it?

8.1HD/ALLISON Senior Enthusiast

8.1HD/ALLISON

Posted
Posted
Those heads come with the rockers and rods as well?

 

How did you adjust the rockers? 1/2 turn or 3/4 turn after touching the rods?

 

 

What brand headers and how much were they?

 

 

They are hydraulic lifters, no rocker adjustment.

c4cruiser Enthusiast

c4cruiser

Posted
Posted

Lots of oil sludge in that one pic :lol: Was that caused by the leak or just not changing oil at recommended intervals?

 

Our shop has seen a number of Chevy and GMC pickups and vans with a crack around the center head bolt. We don't try to fix the heads at all as it's quicker to get replacement heads and get the vehicle back in service either the same day or overnight. The local Chevy/GMC dealer keeps a supply of replacement heads in stock. And we replace both heads even if just one has the typical crack.

 

I believe there is a TSB out on this problem. Recommending the sealing tabs sounds like a cop-out. There can also be cracks around the combustion chamber so have a block test done to see if there are combustion gasses in the coolant.

 

I know we get a good deal from the dealer on a pair of replacement heads so maybe GM is trying to help out with repair costs. It's interesting that we have found the replacement heads we get are Castech's. Hopefully these new castings have fixed the weak point around that one bolt.

wavery Enthusiast

wavery

Posted
Posted
Lots of oil sludge in that one pic :lol: Was that caused by the leak or just not changing oil at recommended intervals?

 

Our shop has seen a number of Chevy and GMC pickups and vans with a crack around the center head bolt. We don't try to fix the heads at all as it's quicker to get replacement heads and get the vehicle back in service either the same day or overnight. The local Chevy/GMC dealer keeps a supply of replacement heads in stock. And we replace both heads even if just one has the typical crack.

 

I believe there is a TSB out on this problem. Recommending the sealing tabs sounds like a cop-out. There can also be cracks around the combustion chamber so have a block test done to see if there are combustion gasses in the coolant.

 

I know we get a good deal from the dealer on a pair of replacement heads so maybe GM is trying to help out with repair costs. It's interesting that we have found the replacement heads we get are Castech's. Hopefully these new castings have fixed the weak point around that one bolt.

I would certainly expect the new heads to be Castech's. I'm sure that GM made them correct the issue and supply them with a number of replacement heads (probably at no cost) or lose their contract plus be sued for non-performance.

 

I would feel much more comfortable with new heads from Castech then someone taking the defective heads, repairing them and reselling those same defective heads. Don't get me wrong, they may do a great job of repairing the defective heads....... I just wouldn't feel good about it.

pm26 Senior Enthusiast

pm26

Posted
Posted

When did GM stop using Castech heads? Were they installed in 2006 5.3 liter models? And if so, only some trucks got them? Is there any way to track this down by the VIN or the engine serial number? Are all Castech heads defective? If not, what percentage?

txab Senior Enthusiast

txab

Posted
Posted
When did GM stop using Castech heads? Were they installed in 2006 5.3 liter models? And if so, only some trucks got them? Is there any way to track this down by the VIN or the engine serial number? Are all Castech heads defective? If not, what percentage?

You're in the range period. Pull the cover and begin looking for the casting marks. That's how it's done.

wavery Enthusiast

wavery

Posted
Posted
What do these markings look like and where are they located??

 

Click on the link in post #8. It shows you exactly.

pm26 Senior Enthusiast

pm26

Posted
Posted
What do these markings look like and where are they located??

 

Click on the link in post #8. It shows you exactly.

 

 

Thanks.

03GMC5.3 Enthusiast

03GMC5.3

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Those heads come with the rockers and rods as well?

 

How did you adjust the rockers? 1/2 turn or 3/4 turn after touching the rods?

 

 

What brand headers and how much were they?

 

 

the heads came with valves and springs...rockers and rods were just cleaned up and re used....there are no adjustment with these rockers just bolt em down...there is a special way to torque them that is explained in the chilton manual...the headers are pacesetters that i ceramic coated myself....i paid 200 for headers and 20 for the ceramic vht paint....that stuff really works...cleaned them up well 2 coats high temp primer and 3 coats high temp ceramic holding up suprisingly well.

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